Diffusion and reaction in a fractal catalyst pore—III. Application to the simulation of vinyl acetate production from ethylene
✍ Scribed by Marc-Olivier Coppens; Gilbert F. Froment
- Book ID
- 104107426
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 766 KB
- Volume
- 49
- Category
- Article
- ISSN
- 0009-2509
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✦ Synopsis
This paper discusses an application of the fractal pore model introduced by Coppens and Froment (1994a,b): the gas phase production of vinyl acetate from ethylene and acetic acid on a Pd/AI203 catalyst. The true fractal morphology of the alumina surface has to be accounted for, because the predicted concentrations and fluxes differ in a nontrivial way from what would be calculated for a smooth cylindrical pore. These differences are a result of the influence of the fractal morphology on the Knudsen diffusivities and, indirectly, on the local reaction rates. A plot of the effectiveness factor as a function of the generalized fractal pore Thiele modulus illustrates the latter effect. In short fractal pores, the amounts reacted are seven times larger than in smooth cylindrical pores of the same length. Over large distances, on the other hand, the diffusional limitations can even lead to slightly less conversion in a fractal than in a smooth cylindrical pore of the same length.